Hot-air furnace



Oct. 26 1926. 1,604,833

W. V. LINDSAY HOT AIR FURNACE Filed March 19, 1926 3 Sheets-Sheqt 1 Gili- H t M CK/T/GIKK? 1 1 m W wk 'i M w ex '1.

' W. V. LINDSAY Oct. 26

HOT AIR FURNACE Filed March 19, 1926 3 Sheets-Shoot 3 Patented Oct. 26,1926.

NIT D srars WILLIAM V. LINDSAY, OF WINONA, MINNESOTA.

nor-AIR FURNACE;

Application filed March 19, 1926. Serial No, 95,921.

This invention relates to a hot air furnace of. the down draught type,which is so constructed that the air to be heated is.

brought into contact with a very large amount of radiating surface whichis heated by the fire or products of combustion.

Practically-all of the heat value of the fuel is utilized before theproducts of combustion pass out of the furnace. The invention alsoprovides a furnace so constructed that it can be easily built andassembled and which will be simple and efiicient in construction andoperation.

In the drawings:

Figure l is a vertical section through the furnace with parts omitted.

Figure 2 is a similar section omitting some parts shown in Figure 1 andillustrating others not shown therein.

Figure 3-is a section on the line 3-3 of Figure 1. I o

Figure4 is a section on the line 4-4 of Figure 2. a

Figure 5 is a section on the line 55 of Figure 2.

t Figure 6 is a section on F'gure 2.

the line 66 of The furnace proper is composed of six sections which maybe constructed separately and assembled to form the furnace.

sections comprise an ash box A, fire box B,

three superheater sections G, D and E, and

a fire dome F. Surrounding the whole and spaced therefrom at a properdistance, de-

pending upon the size of the furnace, is

a casing G which may be formed of galvanized sheet steel, brick, orother suitable material.

The bottom of the casing G is provided with one or more inlet pipes 1which may be extended to any suitable point for the reception of theincoming air to be heated The "top of the casing G is provided with aplurality of outlet pipes 2 which are suitably connected to the hot airsystem of the building. The construction and arrangements of these pipesmay be such as desired.

A plurality of pipes 3 illustrated in the These fitted in the outer wallof the bottom section andcommunicating with the chamber pars tiallysurrounding the ash box. At their upper ends these pipes 3 are connectedto similar elbows or extensions ofthe dome F Throughout theillustrations; the movedicated by. arrows with single heads while themovement of the air which is heated and transmitted to the hot airsystem of the H shown in full lines in Figure 3 and in dotted lines inFigures land 2; which flue communicates with the stacker chimney.

Referring particularly to Figures 2 and 6,

it is noted that apipe'o is connected at its ment of the'products ofcombustion is ini upper end to the superheater section It and, t

extends downwardly,having an open lower end slightly above the inletpipe 1. .The superheatersection E has an upper circular passage 7 and atransverse passage 8 leaving similar passageways "9 through which passthe products of combustion. At the opposite side of the superheatersection E is an opening 10 through which the heated air passes intov thespace within the casing G. l

A similar pipe ll is attached at its upper end to the superheatersection D and we tends downwardly terminating at approximately the samelevel as the lower end of the pipe 6. The air to be heated'passesthrough this pipe 11 into the superheater section D which is shown incross-section in Figure 5 and has an annular portion surthrough whichthe air passes into the space within the furnace casing Gr. 1

As shown in Figure 4, a similar pipe 14 is connected at its upper endwith the superheater section C and its open lower end terminates insubstantially the same plane as the pipes 6 and 11. A comparison ofFigures 4 and 6 will show that the superheater section G issubstantially the same as E except arranged in a different manner. Itprovides a peripherial passage and a central passage 16 for the air tobe heated and similar passageways 17 intermediate for the products ofcombustion. An exit opening 18 opens into the space within the furnacecasingG.

The relative arrangement of the four pipes 3 and the pipes 6, 11 and 14is evident from the sections shown in Figures 3 to 6 inclusive. Strictlyspeaking, the pipes 3 should not appear in Figure 2, but the upper andlower portions thereof are shown to give an idea of the generalarrangement with reference to the pipes 6, 11 and 14:.

The products of combustion and heated closed, substantially all of theheated air and products of combustion will pass downward through theplpes 3 and into the chamber surrounding the bottom of the ash boxexcept on its front side, and thence into the flue H. At anytimedesired, the damper omay be opened partially or completely to allowthe escape of a portion of the heated air and products of combustion.

At the same time the air to be heated is passing in through the openingsor inlet pipes "1, a portion of this air rises directly in the spacebetween the casing G and the furnace proper and passes out through thepipes 2 into the heating system of the dwelling. This air passes inclosecontact with the outer walls of the furnace section and is heatedthereby. At the same time air passes upward through the pipes 6, 11, and14 and into the superheater sections E, D, and C respectively, whereinit circulates around the walls'of the passages through which theproducts of combustion are passing. It is obvious that the abovedescribed circulation of the products of combustion and heated air fromthe furnace together with the particular distribution of passages forthe air to be heated will result in provid ing a great amount of surfacefrom which radiation will take place and, therefore,

utilizing a larger proportionof the heat ob-' to be noted, that in orderto avoid confusion upon the drawings certain elements have been omittedfrom the sectional views 3 to 6. It is obvious that various detailchanges may be made in the precise construction of the various elementswithout in any way departing from the spirit of the invention, which isto be regarded as limited only by the scope of the appended claims.

I claim as my invention:

1. A hot air furnace comprising an outer casing, and a furnace properwithin said casing and spaced therefrom, said casing being provided withpassages for the inlet and outlet of air to be'heated, and'said furnaceproper including a plurality of superheater sectionsprovided withpassages for the circulation of the air tobe heated and with openingsfor the transit of the proclucts of combustion, and a plurality ofdownwardly extending pipes each open at its lower end and connected atits upper end to one of said sections to admit air to be heated.

2. A hot air furnace comprising an outer casing, a furnace proper withinsaid casing and spaced therefrom, said casing being provided withpassages for the inletand outlet of air to be heated, and said furnaceproper including a plurality of superheater sections provided withpassages for the circulation of the air to be heated and withopeningsfor the transit of the products of combustion, and means separate fromsaid sections for permitting the products of combustion to pass from thetop of the furnace proper to the bottom thereof.

3 A hot air furnace comprising an outer casing, a furnace proper withinsaid casing and spaced therefrom, said casing being provided withpassages for the inlet and outlet of air to be heated, and said furnaceproper including a plurality of superheater sections provided withopenings for the transit of the products of combustion, a plurality ofpipes connected to said superheater sections and having lower open endsnear the bottom of the furnace for the admission of air to be heated,and openings at the opposite edges of said sections for the exit of theheated air.

4. A. hot air furnace comprising an outer casing, a furnace properwithin said casing and spaced therefrom, said casing being provided withpassages for the inlet and outlet of air to be heated, and said furnaceproper including a plurality of superheater sections provided withpassages for the circulation of the air to be heated and with openingsfor the transit of the products of combustion, a fire dome above theupper superheater section, and means for permitting the products ofcombustion to pass from the fire dome to the bottom of the furnaceproper.

5. A hot air furnace comprismg an outer casing, a furnace proper Withinsaid casing and spaced therefrom, said casing being provided Withpassages for the inlet and outlet of air to be heated, and said furnaceproper comprising a plurality of superheater sections, a downwardlyextending pipe connected With each superheater section for the admissionof air to be heated, said pipes being spaced from the outer Wall of thefurnace proper and from said casing, and said sections being providedWith vertical passages for the transit of the products of combustion.

In testimony whereof, I have hereunto subscribed my name.

WILLIAM V. LINDSAY.

